That reflexivity felt a bit weird the first time I thought about it. I type the incorrect character, but reflexively notice and backspace it without even becoming aware of it until a moment later. I thought it'd be related to seeing an unexpected character appearing on the display, but I do it just as quickly and reflexively with my eyes closed.
That being said, there are obviously cases where you mistype (usually a fat-finger or something, where you don't physically recognise that you've pressed multiple keys) and don't appreciate it until you visually notice it or the application doesn't do what you expected. 100ms to react to an unexpected stimulus like that is obviously not useful.
I type a lot while looking away from the monitors, helps me think / avoid the stimulus of the text on the screen. I can tell when I fat finger. It also pissed off the boomers at the bar who thought I was showing off as I was a) typing faster then they could, and b) not looking at the screen, c) sometimes looking blankly past them (I'm really not looking when I do this sometimes).
also I typed this entire thing that way without looking at it other than for red squiggles.
That being said, there are obviously cases where you mistype (usually a fat-finger or something, where you don't physically recognise that you've pressed multiple keys) and don't appreciate it until you visually notice it or the application doesn't do what you expected. 100ms to react to an unexpected stimulus like that is obviously not useful.